The answer is no, at least not safely for your amp. It has to do with being able to evenly divide the ohms of output into whole numbers. You can take a Dual Rec and remove half the tubes and you get a 50 watt output, but you get an even division of the ohms. For instance, if the amp is rated at 4, 8 or 16 ohm load for speaker cabinets, dividing the load in half by removing 2 out of 4 power tubes will yield a whole number of ohm output as well as reducing the output from 100 to 50 watts.
In contrast, if you pull 2 out of 6 power tubes on a Triple Rec, the output is reduced from 150 watts to 100 watts, but the ohm output load is now 2/3 of its original 4, 8 or 16 ohm load, not 1/2, and 2/3 of any of those ohm loads does not yield a whole number for which the speakers are rated. Same thing occurs if you pull 4 out of 6 power tubes...now you have 50 watts, but you have 1/3 ohm load, which still isn't a whole number for which the speakers are rated.
I know it can get a bit complicated, but it really isn't just as simple as going from 150 to 100 to 50 watts. The ohm load on the speakers is important to the safe operation of your amp and your speakers.
